Recently, drip coffee has been popularized instead of instant coffee due to the flavor and high quality, and accordingly, specialty stores for drip coffee and devotees of drip coffee have been increased.
Further, users who want to have drip coffee at home or office can have drip coffee by grinding coffee beans using a specific grinder and extracting liquid of coffee using a filter, or can purchase a specific espresso coffee machine and make drip coffee with the machine.
However, it is possible to have drip coffee at a place with the grinder and the filter, or the espresso coffee machine even without using a specialty store for drip coffee, but it is impossible to have drip coffee at a place without the grinder and the filter, or the espresso coffee machine unless using a specialty store for drip coffee.
That is, it is possible to simply have instant coffee on a journey or outdoors as long as a user has instant coffee, a cup, and hot water, but a grinder and a filter, or an espresso coffee machine that is relatively large in volume is required to have drip coffee in comparison to instant coffee, so it is very difficult and troublesome to have drip coffee on a journey or outdoors.
Accordingly, small grinders and filters are recently used for the lovers of drip coffee to easily carry, but common users have a trouble of preparing and carrying those grinders and filters, and a coffee cup and a thermos bottle for hot water. Further, the flavor and the aroma of drip coffee are lost while liquid coffee made through a grinder and a filter is put into a coffee cup.
Further, the espresso coffee machines on the market are expensive and have difficulty in adjusting the concentration of drip coffee in accordance with users' tastes.
In relation to the present invention, there is Korean Utility Model Application Publication No. 20-2009-000673, titled “A tumbler with filter net container”.